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Image Convert

Free web tool: Image Convert

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최대 50MB, PNG/JPG/WebP/BMP/GIF 파일

About Image Convert

The Image Format Converter is a browser-based tool that converts images between PNG, JPG, and WebP formats using the HTML5 Canvas API. It accepts PNG, JPG/JPEG, WebP, BMP, and GIF input files up to 50MB. The tool loads the image into a Canvas element at its original naturalWidth and naturalHeight, then re-encodes it to the selected output format using canvas.toBlob() with format-specific parameters.

For JPG and WebP output formats, you can adjust the quality parameter from 10% to 100% in 10% increments, controlling the lossy compression level. PNG output is always lossless (the quality parameter is ignored). After conversion, the tool displays a preview of the converted image along with a size comparison showing original file size and converted file size, helping you evaluate the trade-off between quality and file size.

All image processing happens entirely in the browser using the Image element and Canvas API. No image data is uploaded to any server. The conversion flow is: file selection, Image element loading, Canvas drawing at full resolution, toBlob() encoding with the chosen MIME type (image/png, image/jpeg, or image/webp), and blob URL generation for preview and download. This makes it suitable for quick batch-free format conversions without installing software.

Key Features

  • Convert between 3 output formats: PNG (lossless), JPG (lossy, adjustable quality), and WebP (lossy, adjustable quality)
  • Accepts 5 input formats: PNG, JPG/JPEG, WebP, BMP, and GIF files up to 50MB
  • Quality slider for JPG and WebP output: 10% to 100% in 10% steps (PNG ignores quality as it is lossless)
  • File size comparison panel showing original size and converted size for format efficiency evaluation
  • Full-resolution conversion preserving original naturalWidth and naturalHeight dimensions
  • Image preview of the converted result with responsive max-height containment
  • One-click download with automatic filename extension change (.png, .jpg, or .webp)
  • 100% client-side processing using Canvas toBlob() API — no server upload or external dependencies

Frequently Asked Questions

What image formats can I convert from and to?

You can input PNG, JPG/JPEG, WebP, BMP, and GIF files. The tool converts to three output formats: PNG (lossless, no quality setting), JPG (lossy, with adjustable quality from 10-100%), and WebP (lossy, with adjustable quality from 10-100%). Select your desired output format before uploading the file. The conversion uses canvas.toBlob() with the corresponding MIME type.

How does the quality slider affect the conversion?

The quality slider (10-100%) controls the lossy compression level for JPG and WebP output. At 90%, you get high visual quality with moderate compression. At 50%, file size is significantly reduced but some artifacts may be visible. For PNG output, the quality slider is hidden because PNG always uses lossless compression. The default quality is 90%, which provides a good balance for most use cases.

Why would I convert PNG to JPG or WebP?

PNG files use lossless compression, making them larger than necessary for photographs. Converting to JPG at 80-90% quality can reduce file size by 60-80% with minimal visible quality loss. WebP typically produces 25-35% smaller files than JPEG at equivalent visual quality. For web optimization, converting large PNG photos to JPG or WebP significantly improves page load times.

Why would I convert JPG to PNG?

Converting JPG to PNG is useful when you need lossless image storage for further editing (preventing additional JPEG compression artifacts from re-saving), when you need transparency support (though the converted PNG will not have transparency since JPEG does not support it), or when working with software that requires PNG input. Note that the PNG will be larger than the JPEG since PNG uses lossless compression.

Does converting between formats lose image quality?

Converting to PNG is lossless — no quality is lost regardless of the input format. Converting to JPG or WebP applies lossy compression, so some quality loss occurs (controlled by the quality slider). If you convert a JPG to PNG and back to JPG, each JPG encoding step introduces additional compression artifacts. For best quality preservation, minimize the number of lossy conversions.

What is the maximum file size I can convert?

The tool accepts files up to 50MB. Since conversion uses the browser's Canvas API, the practical limit depends on your device's available RAM and the image's pixel dimensions. Very large images (e.g., 10000x10000 pixels) may cause memory issues on devices with limited RAM. For most standard images and photographs, the 50MB limit is more than sufficient.

Is my image data sent to a server?

No. All conversion happens entirely in your browser. The image file is read using URL.createObjectURL() to create a local reference, loaded into an Image element, drawn onto a Canvas, and re-encoded using canvas.toBlob() — all in browser memory. No image data is transmitted over the network. The converted file exists only as a local blob URL.

What is the difference between WebP and JPG for web images?

WebP is a modern image format developed by Google that typically produces 25-35% smaller files than JPEG at equivalent visual quality. WebP also supports transparency (like PNG) and animation (like GIF). However, JPEG has broader compatibility with older browsers and legacy software. For modern web applications, WebP is the preferred format; for maximum compatibility, JPEG is safer. This tool lets you convert to either format to compare results.